Question For the Battery Guys

[mpdigger]

I have a Motor Guide 36v motor. Went fishing the other day and noticed my speed was "slow" on high speed. Checked the prop for weeds, line, etc. nothing there, got the meter out, only ha 24 volts to the plug. Checked Batteries, (3 Optima blue tops) 2 batteries had 12.6 volts the other showed "nothing".) Saw the line from the charger to that battery somehow got disconnected) When I got home plugged in charger next morning battery showed 13.6v.
My question is wouldn't the 2 batteries trickle charged to the dead one???
Next question is what battery do you all recommend??? Can I go with a Deep Cycle 27 Series? I have 31's now, tying to save some weight.

Thanks, Mike

[Ed R]

I have a Motor Guide 36v motor. Can I go with a Deep Cycle 27 Series? I have 31's now, trying to save some weight.

Thanks, Mike

Go with three 50ah Lithium batteries. Will save weight and space. 14lbs each, total weight 42lbs.

[Ann-Marie]

<SNIP>When I got home plugged in charger next morning battery showed 13.6v.
My question is wouldn't the 2 batteries trickle charged to the dead one???
<SNIP>
Thanks, Mike

No. Batteries in series will not only discharge each other but when one goes dead the others force current through it and rapidly destroy it.
The voltage on a charger does not show how much charge you have, only how much the current capacity has been charged. A good battery will take extended time to show 13.6 because it takes time to get in the amp-hours. A dead battery may only have a capacity of a few amp-hour capacity left so it will charge to 13.6 in a few seconds.

Avoid using 24 volt Lithium batteries if you ever plan to use a Trollbridge to charge from the starting battery. 24 volt batteries are not compatible with the Trollbridge series.

[mpdigger]

Thanks, I still show 13.4volts after taking off of charge.

Still will probably change them out because of their age........Still will stick to an agm battery. Trying to locate a lighter one

[billnorman1]

Once a battery in series goes "dead" the others will actually make its' situation worse because batteries that are discharging (working) have current going in the opposite direction of charging. This can and will in many situations reverse the polarity of their individual cells.
That battery may fail very soon in operation, closely monitor the voltage after you use it before charging.